In a NAND-type flash memory (a semiconductor memory device), tightening the space between adjacent charge accumulation layers due to higher integration requires thinning the film thickness of the charge blocking layer (a second gate insulating film) formed so as to cover the charge accumulation layers. However, thinning the charge blocking layer causes electrons (a charge) accumulated in the charge accumulation layers to be prone to leak out through the charge blocking layer into the control gate electrode, and thus the charge retention properties of the charge accumulation layers tend to deteriorate.